1. Field of the Invention
This invention relates to catalysts and catalyst supports comprising silica supported on alumina, their preparation and use. More particularly, this invention relates to cracking catalysts and catalyst supports comprising silica supported on alumina which are prepared by compositing particles of silica or hydrated silica with particles of alumina and subjecting said composite to high temperature steaming at a temperature of at least about 500.degree. C. for a time sufficient for at least a portion of said silica to react with and to disperse over the exterior and internal pore surface of the alumina.
2. Background of the Disclosure
Use of silica-alumina composites as catalysts and as catalyst support materials is well known to those skilled in the art. These catalysts are prepared in many different ways such as co-precipitation, various co-gel techniques, by contacting alumina with various silica precursor salt such as organo-silanes, including alkoxy silanes followed by calcination of the so-formed composite to produce the desired silica-alumina material. Use of the latter techniques enables one to obtain an alumina whose surfaces are partly or completely covered with silica as opposed to a homogeneous or heterogeneous silica-alumina compound.